As has been known, vehicles are equipped with wipers that wipe water droplets and the like off a window glass through repetitive reversal motions (for example, refer to Patent Document 1). The drive source for wipers is a wiper motor such as a reversing wiper motor. The wipers are operated by the wiper motor to perform reversal motions, while wiping the surface of a window glass. A wiper control device for controlling operation of a wiper motor controls the wiper motor such that the wiper motor rotates at a constant speed, that is, the rotational speed of the wiper motor is constant, even if the voltage of a vehicle battery changes in a predetermined range (for example, from 10 to 16 V). Such operation is performed both in an internal combustion engine vehicle and an electrically driven vehicle (a hybrid car and an electric vehicle).